XTE J1814-338 as a dark matter admixed neutron star

TL;DR

This paper investigates the properties of the ultracompact object XTE J1814-338 as a dark matter admixed neutron star, analyzing its physical characteristics and comparing it with other pulsars to understand its nature.

Contribution

It introduces a detailed model of dark matter admixed neutron stars to explain the compactness of XTE J1814-338, including its equation of state and macroscopic properties.

Findings

Dark matter admixture can account for the star's low radius

The star's equation of state suggests a high Fermi momentum of dark matter

Comparison indicates unique features of XTE J1814-338 among pulsars

Abstract

The existence of the ultracompact object XTE J1814-338, with an inferred mass and radius of $M$ = 1.21 $\pm$ 0.05 $M_\odot$ and R = 7.0 $\pm$ 0.4 km, presents a great challenge for the theory of neutron stars. Within this context, we revisit the theory of dark-matter-admixed neutron stars and infer the physical properties of this compact object, such as the Fermi momentum of dark matter necessary to compress the star at such low radius, its equation of state, speed of sound, and some macroscopic properties, such as the moment of inertia and the dimensionless tidal parameter. We also compare the physical properties of the XTE J1814-338 with other pulsars, such as the canonical 1.4 M$_\odot$, the PSR J0740 + 6620, and the HESS J1731-347.